Burning autofuel, I also shut off the fuel & run the carb bowl dry if
it won't be flown for a week or more. Fresh fuel in the bowl & primer
really helps.

I've run over 6500 gallons of mogas through Atlas, and he (the plane,
that is) was run on exclusively mogas by previous owner(s) for almost
10 years.

I've never heard of what you're talking about before. Are you saying
that mogas starts to go bad after a WEEK?
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"